X-linked retinoschisis (XLRS) is a rare hereditary disorder characterized by bilateral stellate maculopathy and peripheral retinoschisis. The schisis cavities are usually first noted in the inferotemporal quadrant and often progress to involve the entire peripheral retina. This process often commences within the first year of life and is associated with a wide range of phenotypic expression.1 Histopathologic studies have demonstrated a splitting of the retina at the nerve fiber layer.2 A gene responsible for XLRS, XLRS-1, which maps to Xp22.2, has been cloned and sequenced. The predicted protein sequence contains a highly conserved motif implicated in cell-cell interaction and, thus, may be active in cell adhesion processes.3 We report the clinical and electrodiagnostic phenotype associated with a missense point mutation within the fifth exon of this gene that replaces the normal arginine residue with a histidine residue at codon 141 in a family of Hispanic origin.